A recurrent genetic cause of autism

In a 2008 study, a group of researchers including James F. Gusella discovered that a stretch of DNA containing several genes is missing from chromosome 16 in about one percent of people affected or suspected to be affected with autism. The researchers hope to identify the specific genes located in this chromosomal region that play a role in causing autism. The defect in chromosome 16 is extremely rare in the general population, and the fact that it spontaneously originates in the individual diagnosed with autism — rather than being inherited from unaffected parents — suggests that the defect drives the development of the disorder. In the same study, the researchers noticed that a duplication, rather than a deletion, of the same stretch of DNA might also predispose individuals to developing autism, albeit in an inherited and less consistent manner. To test their hypothesis, Gusella and colleagues plan to use gene sequencing and bioinformatics technology to determine which of the genes affected by the deletion or duplication of chromosome 16 contribute to autism. Once the genes are identified, the researchers plan to use cutting-edge methods to generate stem cells and convert them into neurons and other types of cells, which will then be used in models to test the effects of the autism-linked genes. Besides uncovering the role of particular genes, the researchers hope these laboratory models can be used in studies of other autism-linked genes to shed light on the molecular basis for the development of autism.